Interplay between Composition, Structure, and Properties of New H3PO4-Doped PBI4N鈥揌fO2 Nanocomposite Membranes for High-Temperature Proton Exchange Membrane

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• 作者：Graeme Nawn ; Giuseppe Pace ; Sandra Lavina ; Keti Vezz霉 ; Enrico Negro ; Federico Bertasi ; Stefano Polizzi ; Vito Di Noto
• 刊名：Macromolecules
• 出版年：2015
• 出版时间：January 13, 2015
• 年：2015
• 卷：48
• 期：1
• 页码：15-27
• 全文大小：609K
• ISSN：1520-5835

文摘

Polybenzimidazole (PBI) has become a popular polymer of choice for the preparation of membranes for potential use in high-temperature proton exchange membrane polymer fuel cells. Phosphoric acid-doped composite membranes of poly[2,2鈥?(m-phenylene)-5,5鈥?bibenzimidazole] (PBI4N) impregnated with hafnium oxide nanofiller with varying content levels (0鈥?8 wt %) have been prepared. The structure鈥損roperty relationships of both the undoped and acid-doped composite membranes are studied using thermogravimetric analysis, modulated differential scanning calorimetry, dynamic mechanical analysis, wide-angle X-ray scattering, infrared spectroscopy, and broadband electrical spectroscopy. Results indicate that the presence of nanofiller improves the thermal and mechanical properties of the undoped membranes and facilitates a greater level of acid uptake. The degree of acid dissociation within the acid-doped membranes is found to increase with increasing nanofiller content. This results in a conductivity, at 215 掳C and a nanofiller level x 鈮?0.04, of 9.0 脳 10^鈥? S cm^鈥? for [PBI4N(HfO₂)_x](H₃PO₄)_y. This renders nanocomposite membranes of this type as good candidates for use in high temperature proton exchange membrane fuel cells (HT-PEMFCs).